Sulphurization of organic polysulphides



.basic substance.

atented A s, 194i UNITED STATES PATENT OFFICE I SULPHURIZATION iZ ZZtGANIG POLYBUL- I PHIDES John F. Olin, Grosse lie, Mich, assignor to The Sharples Solvents Corporation, Philadelphia,

No Drawing. Application October 10, 1939,

Serial No. 298,768

2 Claims. (or. 260-125) This application is a continuation in part of my prior application, Serial Number 233,800, filed valuable uses have been found for organic compounds containing a relatively large percentage of sulphur or having sulphur to sulphur linkages in the molecule. Among the more .important commercial developments of this nature are the compounding-of extreme pressure lubricants and the acceleration of rubber treating processes. in both capacities di-, tri-, and other poly-sulphides of an organic nature arenow generally recognized as materials of great and increasing commercial value.

The preparation of these compounds has, however, been a problem of considerabledifiiculty from the industrial standpoint. Recently, a process for the preparation of di-sulphides by the reaction between a hydrogen poly-sulphide and an olefin has been described in Letters Patent 2,061,018 to Wallace H. Carothers. This reaction gives satisfactory results in connection with those unsaturated aliphatic compounds having highly reactive multiple bonds, but is of relatively minor importance as a general method of preparation. An improvement on the Carothers technique is described in Letters Patent 2,061,019, issued to Carter and Downing. according to the latter process. the poly-sulphide of the Carothers reaction is formed in the reaction mixture by the action of hydrogen sulphide, and sulphur on a sulphydryl radical attached to an alkyl, allcyclic, cyclic, or heterocycllc radical, except compounds in which a single sulphur atom is doubly linked directly to one or more such radicals, e. g., an alkyl mono-sulphide or thiophene. It involves the preparation of useful organic compounds of sulphur from relatively inexpensive raw materials.

This is of course subject to the" containing compounds having a sulphur atom or The formation of compounds of the nature of dl-alkyl (ii-sulphides from mercaptans is generally regarded as an oxidation reaction and prior to this invention has been caused by treatment with oxidizing agents such as oxygen bearing gases, acids and oxides of nitrogen, chloratesand the like. In view of the fact that the present invention provides a means to convert (ll-sulphides to trl-sulphldes and tri-sulphides to tetrasulphides, etc., it is found advisable to use the term sulphurlzation" to characterize the reaction involved. The novel reaction of this invention is achieved by reacting poly-sulphides with elemental sulphur in the presence of a very small amount of a basic catalyst.

Example I I Sulphurizatz'on of di-liutyl di-suZphide.-To 242 g. of di-n-butyl (ii-sulphide and 75 g. of sulphur was added 5 cc. of mono-butyl amine. The mixture was refluxed for 15 minutes and upon filtration and distillation the reaction mass was foun to contain:

(1) To 115C. at 10 mm. (di-n-butyl disulphide) g 96 (2) 115-140 C. at 10 mm. (di-n-butyl tri-sulphide) "g" 128 (3) Residue g t0 lt'zcamplell at 40 mm. pressure, unreacted di-methyl di-sulphlde is obtained. The next cut, boiling between and C. at 18 mm. pressure consists of dimethyl tri-sulphide, which is a very pale, yellow colored, oil. The residue of the distillation ll believed to be a mixture of (ii-methyl tetra-sulphide and sulphur.

Example ill I Sulphurizatz'on of di-isopropyl di-sulphide.-

300 g. of di-isopropyl di-sulphide, boiling between and C. at 25 mm. pressure, which has been obtained by the sulphurization of i50 propyl mercaptan, are treated with 64 g. of $111 phur and one cc. oi tri-butyl amine at 0. for 8 hours. After washing, as in Example H,

the reaction mixture is distilled. Di-isopropyl disulphide, is obtained in the out boiling up to 105 C. at 25 mm. The second cut, boiling be tween 105 and 125 C. at 25 mm. pressure, consists principally oi di-isopropyl tri-sulphide.

The residue in the distilling flask is believed to' be higher di-isopropyl sulphides and sulphur.

Example 'IV sulphurization of (ii-tertiary butyl di-sulphz'de.--356 g. of di-tertiary butyl di-sulphide, obtained by the sulphurization of tertiary butyl mercaptan, are treated at 125 C. for a period of 8 hours with 64 g. of sulphur and cc. of diamyl amine. After washing the reaction product as in Examples II and m, the product is vacuum distilled, as in those examples. Unchanged ditertiary butyl di-sulphide is recovered in the cut boiling up to 100 C. under 10 mm. pressure, A second cut, consisting of di-tertiary butyl tri sulphide, is recovered between 100 and 112 C, at 10 mm. pressure. It was a yellow oil. A third cut, likewise a yellow oil consisting principally of di-tertiary butyl tetrasulphide, is obtained as a fraction boiling between 130 and 145 C. at 10 mm. pressure. The residue in the distilling flask consists of higher sulphides together with some elemental sulphur.

The catalysts suited to the purposes of this invention include those compounds havingan alkaline reaction such as oxides and hydroxides of the metals, alkali metal sulphides, ammonia, amines, etc., but the amines are preferred be. cause of their solubility in the reaction mixtures. It has been found that the aryl amines, such as aniline, are operative for the present purpose, as

arches? well as the aliphatic amines such as those described in the specific examples given above. Temperature apparently may vary over a wide range, but sulphurization of poly-sulphides usually proceeds more rapidly at elevated temperatures. Pressure is unnecessary and the hydrogen sulphide formed by the reaction may be permitted to escape without adverse effect. This latter factor and the small amounts of catalyst employed clearly indicate that the present reaction is difierent in nature from previous processes using similar catalysts for the preparation of poly-sulphides from olefins.

Modifications will be obvious to those skilled in the art and I do not therefore wish to be limited except by the scope of the sub-joined claims.

I claim:

1. The process which comprises reacting a compound ogf the type wherein R and R are radicals chosen from the class consisting of aliphatic, alicyclic, aromatic and heterocyclic groups and S denotes sulphur, with sulphur in the presence of a catalytic amount of a basic catalyst.

2. The process which comprises reacting a compound of the type Wi -R wherein R and R are radicals chosen from the class consisting of aliphatic, alicyclic, aromatic and heterocyclic groups and S denotes sulphur, with sulphur in the presence of a catalytic amount of an amine.

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